title: Inhibitory effect of cervical trachea and chest wall vibrations on cough reflex sensitivity and perception of urge-to-cough in healthy male never-smokers.
abstract: BACKGROUND
  Non-pharmacological options for symptomatic management of cough are desired. Although chest wall mechanical vibration is known to ameliorate cough reflex sensitivity, the effect of mechanical vibrations on perceptions of urge-to-cough has not been studied. Therefore, we investigated the effect of mechanical vibration of cervical trachea, chest wall and femoral muscle on cough reflex sensitivity, perceptions of urge-to-cough as well as dyspnea.
  
  
  METHODS
  Twenty-four healthy male never-smokers were investigated for cough reflex sensitivity, perceptions of the urge-to-cough and dyspnea with or without mechanical vibration. Cough reflex sensitivity and urge-to-cough were evaluated by the inhalation of citric acid. The perception of dyspnea was evaluated by Borg scores during applications of external inspiratory resistive loads. Mechanical vibration was applied by placing a vibrating tuning fork on the skin surface of cervical trachea, chest wall and femoral muscle.
  
  
  RESULTS
  Cervical trachea vibration significantly increased cough reflex threshold, as expressed by the lowest concentration of citric acid that elicited five or more coughs (C5), and urge-to-cough threshold, as expressed by the lowest concentration of citric acid that elicited urge-to-cough (Cu), but did not significantly affect dypnea sensation during inspiratory resistive loading. On the other hand, the chest wall vibration not only significantly increased C5 and Cu but also significantly ameliorated the load-response curve of dyspnea sensation.
  
  
  CONCLUSIONS
  Both cervical and trachea vibrations significantly inhibited cough reflex sensitivity and perception of urge-to-cough. These vibration techniques might be options for symptomatic cough management.
authors.affiliation: Department of Internal Medicine and Rehabilitation Science, Tohoku University Graduate School of Medicine, Seiryo-machi 1-1, Aoba-ku, Sendai,, 980-8574, Japan. sebihara@med.tohoku.ac.jp.
authors.forename: Naohiro
authors.initials: N
authors.lastname: Kashiwazaki
authors.forename: Satoru
authors.initials: S
authors.lastname: Ebihara
authors.forename: Peijun
authors.initials: P
authors.lastname: Gui
authors.forename: Norihiro
authors.initials: N
authors.lastname: Katayama
authors.forename: Kumiko
authors.initials: K
authors.lastname: Ito
authors.forename: Ryuhei
authors.initials: R
authors.lastname: Sato
authors.forename: Chika
authors.initials: C
authors.lastname: Oyama
authors.forename: Takae
authors.initials: T
authors.lastname: Ebihara
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kohzuki